Re: [DNSOP] Last Call: <draft-ietf-dnsop-refuse-any-07.txt> (Providing Minimal-Sized Responses to DNS Queries that have QTYPE=ANY) to Proposed Standard

Tony Finch <dot@dotat.at> Tue, 21 August 2018 19:31 UTC

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Date: Tue, 21 Aug 2018 20:31:50 +0100
From: Tony Finch <dot@dotat.at>
To: Paul Wouters <paul@nohats.ca>
cc: =?UTF-8?Q?=C3=93lafur_Gu=C3=B0mundsson?= <olafur=40cloudflare.com@dmarc.ietf.org>, draft-ietf-dnsop-refuse-any@ietf.org, Ted Hardie <ted.ietf@gmail.com>, dnsop-chairs <dnsop-chairs@ietf.org>, dnsop <dnsop@ietf.org>, IETF <ietf@ietf.org>
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Subject: Re: [DNSOP] Last Call: <draft-ietf-dnsop-refuse-any-07.txt> (Providing Minimal-Sized Responses to DNS Queries that have QTYPE=ANY) to Proposed Standard
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Paul Wouters <paul@nohats.ca> wrote:
> On Tue, 21 Aug 2018, Ólafur Guðmundsson wrote:
>
> > Ted, Would it be acceptable to just do 
> > s/TCP/Connection oriented Transport/ 
>
> For RFC 7901 we used "source-IP-verified transport"

I don't think that's a good idea, because it suggests oversised responses
over UDP with cookies. I wanted minimal-any in order to reduce both UDP
fragmentation and fallback to TCP for all UDP queries from legitimate
clients. (Spoofed queries are dealt with by RRL.)

I suggest:

4.4.  Behaviour over different DNS transports

   A DNS responder MAY behave differently when processing ANY queries
   received over different DNS transports or with different levels
   of client authentication, e.g. by providing a conventional
   ANY response over TCP whilst using one of the other mechanisms
   specified in this document in the case where a query was received
   using UDP.

   Implementers SHOULD provide configuration options to allow operators
   to specify different behaviour over different DNS transports or for
   authenticated clients.

(the TCP/UDP e.g. is just a non-normative example; more outre transports
and options are covered by the normative text)

Tony.
-- 
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